What is dark energy? And could we tap into it?

Before scientists could even attempt to assess the possibility of harnessing dark energy as a source of electricity, we'd have to find it.

If we were able to harness the power of dark energy, however, we'd be using it for a lot more than simply powering our iPhone. Instead, tapping into dark energy could usher in a whole new era of human spaceflight.

Theoretically, a spacecraft that runs on dark energy is possible. According to a paper published in 2008 on arXiv.org, a dark-energy-powered spacecraft may be able to travel faster than the speed of light. The spaceship would actually stay in place while space-time around it was affected.

Sci-fi fans will recognize this as the basic concept of a "warp drive." In fact, one scientist has even created a design for what such a ship capable of traveling warp speeds would even look like.

That, however, is an application we likely won't see in our lifetimes. And dark-energy-powered electronics, cars or buildings aren't coming along anytime soon, either.